Radiographic images, such as X-ray films, and Magnetic resonance imaging ("MRI") and computerized tomograph (CT) transparencies have traditionally been reviewed by a diagnosing physician such as a radiologist on a film viewer, on which a series of images in a patient study are displayed in groups of two or more. Different image series, generated by processing the data captured during a patient scan in different ways, are typically provided. The different image series may display the same portions of the patient's anatomy but processing reduces the amount of information in the image to allow for films having sufficient pixel depth to provide the detail needed for diagnosis in the tissue of interest. The film viewer may be a static light box or a motorized film viewer. A motorized film viewer consists of vertically positioned light boxes and an endless belt on which the films are mounted and which passes the films in front of the light boxes. Motorized film viewers are controlled by the radiologist using foot pedals which activate the motorized viewer to cause the films to be moved to the left or to the right (or in some cases, up and down) to permit viewing of the desired portions of the film series. The images are usually presented in a standard sequence, usually in the order of image capture. The radiologist will typically dictate a medical study into a tape recorder while viewing the films, for later transcription. The films and transcribed dictation are stored in a patient's file.
Filmless image systems have also been proposed and used. Filmless systems have been used in connection with handling both MRI images, and computer tomography images generated by processing X-ray image data to generate a series of "slices" through the human body. Such systems historically have presented all the image data captured by the MRI or tomography equipment, as opposed to in film images (where the medical technician will expose films only for selected series of images of clinical interest). Filmless systems have been proposed in which a series of images are presented to the diagnosing physician simultaneously. One such system is described in U.S. Pat. No. 5,452,416 to Hilton.
U.S. Pat. No. 5,235,510 to Yamada et al. discloses a computer-aided diagnosis (CAD) system for medical use. The system generates digital images from medical images, such as X-ray film, computed tomography scans and magnetic resonance images, and creates a diagnosis of the digitized medical images using CAD algorithms. A disadvantage to this system is that a doctor may not be able to easily display and compare the digitized images and the non-digitized images at the same time.
Although a medical facility may have the technology to display and examine filmless images, a radiologist may desire to view film and filmless images at the same time. For instance, the radiologist may be comparing recent filmless images with past film images or may be comparing its filmless images with film images from another hospital.
What is desired, therefore, is a system in which medical personnel can display and compare corresponding film and filmless medical images at the same time.